The present invention concerns a thrust bearing made of synthetic resin, particularly, it relates to a thrust bearing made of synthetic resin assembled into a strut-thrust type suspension (MacPherson type) for use in four wheel cars.
Generally, a strut-thrust type suspension is mainly used for the front wheels of four wheel cars in which coil springs are combined with a strut assembly incorporating an oil pressure type shock absorber in an outer cylinder integrated with a main shaft. The suspension described above includes such a type in which a piston rod of a strut assembly is rotated when the assembly is rotated together with coil springs by a steering operation and another type in which the piston rod is not rotated. In both of the types, a thrust bearing is required between the mounting member of the assembly to a vehicle body and the upper spring seat of the coil assembly for allowing the smooth rotation of the strut assembly.
Roller bearings using balls or needles, or sliding type thrust bearings made of synthetic resin have been employed so far in these portions.
A dust seal made of an elastic rubber member is mounted at the outer circumference of the sliding surface for the thrust bearing made of synthetic resin for preventing the intrusion of dust or the like from the outside of the bearing to the sliding surface.
In the prior art described above, since a dust seal is disposed to the outer circumference of the sliding surface for the thrust bearing, there is a drawback that the sliding frictional force is increased upon steering operation thereby requiring great steering force.